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/**
* \file random.h
*
* \brief This file contains the prototypes of helper functions to generate
* random numbers for the purpose of testing.
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#ifndef TEST_RANDOM_H
#define TEST_RANDOM_H
#include "mbedtls/build_info.h"
#include <stddef.h>
#include <stdint.h>
typedef struct {
unsigned char *buf; /* Pointer to a buffer of length bytes. */
size_t length;
/* If fallback_f_rng is NULL, fail after delivering length bytes. */
int (*fallback_f_rng)(void *, unsigned char *, size_t);
void *fallback_p_rng;
} mbedtls_test_rnd_buf_info;
/**
* Info structure for the pseudo random function
*
* Key should be set at the start to a test-unique value.
* Do not forget endianness!
* State( v0, v1 ) should be set to zero.
*/
typedef struct {
uint32_t key[16];
uint32_t v0, v1;
} mbedtls_test_rnd_pseudo_info;
/**
* This function just returns data from rand().
* Although predictable and often similar on multiple
* runs, this does not result in identical random on
* each run. So do not use this if the results of a
* test depend on the random data that is generated.
*
* rng_state shall be NULL.
*/
int mbedtls_test_rnd_std_rand(void *rng_state,
unsigned char *output,
size_t len);
/**
* This function only returns zeros.
*
* \p rng_state shall be \c NULL.
*/
int mbedtls_test_rnd_zero_rand(void *rng_state,
unsigned char *output,
size_t len);
/**
* This function returns random data based on a buffer it receives.
*
* \p rng_state shall be a pointer to a #mbedtls_test_rnd_buf_info structure.
*
* The number of bytes released from the buffer on each call to
* the random function is specified by \p len.
*
* After the buffer is empty, this function will call the fallback RNG in the
* #mbedtls_test_rnd_buf_info structure if there is one, and
* will return #MBEDTLS_ERR_ENTROPY_SOURCE_FAILED otherwise.
*/
int mbedtls_test_rnd_buffer_rand(void *rng_state,
unsigned char *output,
size_t len);
/**
* This function returns random based on a pseudo random function.
* This means the results should be identical on all systems.
* Pseudo random is based on the XTEA encryption algorithm to
* generate pseudorandom.
*
* \p rng_state shall be a pointer to a #mbedtls_test_rnd_pseudo_info structure.
*/
int mbedtls_test_rnd_pseudo_rand(void *rng_state,
unsigned char *output,
size_t len);
#endif /* TEST_RANDOM_H */